# -*- coding: utf-8 -*-
from odoo import api, fields, models, exceptions


class Testb(models.Model):
    _name = "m.test.b"

    name = fields.Char(string=u"Code")
    cta = fields.Html(string=u"Content A")
    ctb = fields.Html(string=u"Content B ")

<record id="view_test_form" model="ir.ui.view">
    <field name="name">Test Form</field>
    <field name="model">m.test.b</field>
    <field name="arch" type="xml">
        <form>
            <sheet>
                <group>
                    <field name="name"/>

                    <field name="cta" />
                    <field name="ctb"/>
                </group>
            </sheet>
        </form>
    </field>
</record>

it overflows interface and not down stream.

My image:

i.imgur.com/1rABtha.png

How to fix it?

Thanks.